Method and system for maintaining secure data input and output

Abstract

Methods and systems for enhancing the security of data during input and output on a client computer system are provided to prevent attempts by unauthorized code to access, intercept, and/or modify data. Example embodiments provide obfuscation techniques and security enhanced drivers that use these obfuscation techniques to prohibit unauthorized viewing/receiving of valid data. When the drivers are used together with the various obfuscation techniques, the security enhanced drivers provide mechanisms for “scheduling” the content of the storage areas used to store the data so that valid data is not available to unauthorized recipients. When unauthorized recipients attempt to access the “data,” they perceive or receive obfuscated data. The obfuscation techniques described include “copy-in,” and “replace and restore.”

1 . A method in a computer system for providing a secure display area on a video display device of a video display system, the video display system having video display memory for storing data to be displayed on the video display device, comprising:
 reserving a portion of the video display memory for secure data storage that corresponds to the secure display area;   receiving a request to display valid data in the secure display area, the request including an indication of the valid data;   storing the indicated valid data in a secure data buffer separate from the reserved portion of the video display memory;   storing invalid data in the reserved portion of the video display memory until a predetermined period of time before the data stored in the reserved portion is transferred to the video display device for display; and   at the predetermined period of time, replacing the invalid data stored in the reserved portion of the video display memory with valid data from the secure data buffer wherein the predetermined period of time corresponds to a time required to replace the invalid data in the reserved portion with valid data from the secure data buffer and transfer the reserved portion to the video display device.   
     
     
         2 . The method of  claim 1 , further comprising:
 after the data stored in the reserved portion is transferred to the video display, replacing the valid data stored in the reserved portion of the video display memory with invalid data in the reserved portion of the video display memory.   
     
     
         3 . The method of  claim 1  wherein the valid data is obfuscated prior to storing in the secure data buffer. 
     
     
         4 . The method of  claim 3  wherein obfuscation is performed by at least one of encryption of the valid data and a raster operation applied to the valid data and a mask. 
     
     
         5 . The method of  claim 4  wherein the mask is a bitmap comprising at least one of an encryption key, a company logo, a pattern, an advertisement, and a black region. 
     
     
         6 . The method of  claim 1  wherein the secure data buffer is one of an area in the video display memory, a portion of random access memory in the computer system, a secondary memory that resides on a video card that controls the video display device and storage accessible by other means. 
     
     
         7 . The method of  claim 6  wherein the location of the secure data buffer is one of a user designated, application designated, and system designated location. 
     
     
         8 . A non-transitory computer-readable medium for providing a secure display area on a video display device of a video display system, the video display system having video display memory for storing data to be displayed on the video display device, the computer-readable medium containing instructions that, if executed, will cause a computer system to implement:
 a data receiver that is structured to receive a request to display valid data in the secure display area, the request including an indication of the valid data; and   a video display memory scheduler that is structured to:
 reserve a portion of the video display memory for secure data storage that corresponds to the secure display area; 
 store the indicated valid data in a secure data buffer; 
 store invalid data in the reserved portion of the video display memory until a predetermined period of time before the data stored in the reserved portion is transferred to the video display device for display; and 
 replacing the invalid data with the valid data from the secure data buffer at the beginning of the predetermined period of time. 
   
     
     
         9 . The computer-readable medium of  claim 8  wherein the determined period of time corresponds to a time required to, replace the invalid data stored in the reserved portion of the video display memory with valid data from the secure data buffer and transfer the reserved portion to the video display device. 
     
     
         10 . The computer-readable medium of  claim 8 , wherein the video display memory scheduler is further structured to store invalid data in the reserved portion of the video display memory after the data stored in the reserved portion is transferred to the video display. 
     
     
         11 . The computer-readable medium driver of  claim 8  wherein the secure data buffer is implemented by storing the valid data in the reserved portion of the video display memory as encrypted data. 
     
     
         12 . The computer-readable medium of  claim 8  wherein the secure data buffer is one of an area in the video display memory, a portion of random access memory in the computer system, a secondary memory that resides on a video card that controls the video display device and storage accessible by other means. 
     
     
         13 . The computer-readable medium of  claim 8  wherein the secure data buffer location is one of a user designated, application designated, and system designated location. 
     
     
         14 . The computer-readable medium of  claim 8  wherein the video display memory comprises a frame buffer that stores data that is to be displayed on the video display device and wherein the secure data buffer is a portion of the frame buffer. 
     
     
         15 . The computer-readable medium of  claim 8  wherein the valid data is obfuscated prior to storing in the secure data buffer. 
     
     
         16 . The computer-readable medium of  claim 15  wherein obfuscation is performed by at least one of encryption of the valid data and a raster operation applied to the valid data and a mask.